forked from mia/Aegisub
4bdccb889c
At least on OS X, allocating the buffers is one of the more expensive parts of video playback, and on an arbitrary 720p H.264 file with simple subtitles this cuts CPU usage while playing by about 30%.
105 lines
3.8 KiB
C++
105 lines
3.8 KiB
C++
// Copyright (c) 2013, Thomas Goyne <plorkyeran@aegisub.org>
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//
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// Permission to use, copy, modify, and distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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//
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// Aegisub Project http://www.aegisub.org/
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#include "include/aegisub/video_provider.h"
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#include "options.h"
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#include "video_frame.h"
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#include <libaegisub/make_unique.h>
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#include <list>
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namespace {
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/// A video frame and its frame number
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struct CachedFrame {
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VideoFrame frame;
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int frame_number;
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CachedFrame(VideoFrame const& frame, int frame_number)
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: frame(frame), frame_number(frame_number) { }
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CachedFrame(CachedFrame const&) = delete;
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};
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/// @class VideoProviderCache
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/// @brief A wrapper around a video provider which provides LRU caching
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class VideoProviderCache final : public VideoProvider {
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/// The source provider to get frames from
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std::unique_ptr<VideoProvider> master;
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/// @brief Maximum size of the cache in bytes
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///
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/// Note that this is a soft limit. The cache stops allocating new frames
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/// once it has exceeded the limit, but it never tries to shrink
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const size_t max_cache_size = OPT_GET("Provider/Video/Cache/Size")->GetInt() << 20; // convert MB to bytes
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/// Cache of video frames with the most recently used ones at the front
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std::list<CachedFrame> cache;
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public:
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VideoProviderCache(std::unique_ptr<VideoProvider> master) : master(std::move(master)) { }
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void GetFrame(int n, VideoFrame &frame) override;
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void SetColorSpace(std::string const& m) override {
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cache.clear();
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return master->SetColorSpace(m);
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}
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int GetFrameCount() const override { return master->GetFrameCount(); }
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int GetWidth() const override { return master->GetWidth(); }
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int GetHeight() const override { return master->GetHeight(); }
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double GetDAR() const override { return master->GetDAR(); }
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agi::vfr::Framerate GetFPS() const override { return master->GetFPS(); }
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std::vector<int> GetKeyFrames() const override { return master->GetKeyFrames(); }
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std::string GetWarning() const override { return master->GetWarning(); }
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std::string GetDecoderName() const override { return master->GetDecoderName(); }
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std::string GetColorSpace() const override { return master->GetColorSpace(); }
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std::string GetRealColorSpace() const override { return master->GetRealColorSpace(); }
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bool ShouldSetVideoProperties() const override { return master->ShouldSetVideoProperties(); }
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bool HasAudio() const override { return master->HasAudio(); }
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};
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void VideoProviderCache::GetFrame(int n, VideoFrame &out) {
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size_t total_size = 0;
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for (auto cur = cache.begin(); cur != cache.end(); ++cur) {
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if (cur->frame_number == n) {
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cache.splice(cache.begin(), cache, cur); // Move to front
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out = cache.front().frame;
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return;
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}
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total_size += cur->frame.data.size();
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}
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master->GetFrame(n, out);
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if (total_size >= max_cache_size) {
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cache.splice(cache.begin(), cache, --cache.end()); // Move last to front
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cache.front().frame_number = n;
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cache.front().frame = out;
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}
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else
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cache.emplace_front(out, n);
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}
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}
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std::unique_ptr<VideoProvider> CreateCacheVideoProvider(std::unique_ptr<VideoProvider> parent) {
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return agi::make_unique<VideoProviderCache>(std::move(parent));
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}
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